Hey!
Brent Cross is pretty easy to get to by bus. If you’re coming from central London, you’ve got a few options. The 113 is a good shout; it runs from Oxford Circus all the way to Brent Cross, and it drops you off right outside the shopping centre.
The 189 is another option, starting from Marble Arch and also taking you directly there. If you’re closer to the northern line, you can hop off at Golders Green and grab the 210, which will take you the rest of the way.
The bus stops are right next to the centre, so you can’t miss it!
Hope that helps!